On the morning after storms dumped nearly four and a half inches of rain on the city, Alody Flores woke up and discovered a plastic bucket in her garage half filled with little red “lobsters.” Thursday, August 22, got the most rain of any single day since 1987, and with it hundreds of strange red crustaceans came crawling up out of the murk in River Park, which spans the river between Argyle and Foster.

Flores and her brother Ricardo Antonio, who live nearby, hail from the Philippines, and Antonio used to take crabs from Manila Bay by feeling around for them in the shallows with his bare feet and catching them by hand. So when he heard that a bunch of his neighbors were plucking crustaceans from the river and bringing them home to eat, he thought he’d give them a try.

Flores had seen them before. The previous summer, while she was watching a soccer game in West River Park after a heavy rainfall, the creatures crawled up on the pitch.

They appeared on the east side too, after a big August storm, crawling up to the asphalt bike path and warning off curious dog walkers and joggers by arching their backs and thrusting their claws into the air. It was a seasoned army–some had tiny, malformed or mangled claws, others were amputees. But their size and numbers seemed biblical in the setting of a city park. The next day, evidence of the plague in River Park was gone–except for the ones that had been mauled by children or flattened under car wheels on Argyle.

After Thursday’s storm, dozens of them were creeping through the grass on the east side of the river, where a small stream of storm water was running down the slope toward a chain-link fence and into the river beyond. They were red-and-black-colored crayfish, three to four inches long with freckly bumps on their pincers.

During the storm, water treatment plants were deluged and the Metropolitan Water Reclamation District was forced to release some 1.7 billion gallons of untreated storm water and sewage overflow from the river into the lake. According to the MWRD, the water level on the stretch of the river in River Park–where the North Shore Channel cleaves from the North Branch–can rise and fall rapidly during such events, probably seven or eight feet at times. No one at the MWRD or the Chicago Park District had heard of any over-the-bank flooding on either side of the river there, though a manager at the CPD said he’d spotted landlubbing crayfish further south, in Horner Park.

Irwin Polls, manager of the MWRD’s Aquatic Ecology and Water Quality Section, says he’s occasionally seen crayfish in the river, but certainly not hundreds and usually in shallower parts upstream, above the dam on the North Branch in River Park. The dam’s waterfall churns lots of enriching oxygen into the water, making that particular spot a pretty good fishing hole, by the river’s standards. On the other hand the channel there is particularly deep–9 to 12 feet–and the banks are steep. That’s not a typical environment for crayfish. Polls thinks that they might have been swept over the dam from upstream. In his 30 years with the MWRD, he’s never heard of large numbers of crayfish crawling around on land.

On Friday afternoon Ricardo Antonio was still at it, wading ankle deep on the west side of the river with his neighbor Kim, a small Cambodian woman who speaks little English. Kim stood quietly in the shallows with her arms at her side, staring down at the muddy water lapping the riverbank. Every minute or so she’d lean over and plunge her hand in. In one motion she’d pull up a snapping crayfish, turn, and toss it into Antonio’s blue plastic bucket. A few feet upriver a Latino family was filling its own bucket with a handheld net.

Antonio’s style was more athletic. He’d spot a faint blob of pink in the brown water, crouch over it, and hold his right arm above his head, steadying his aim. Then he’d sweep his hand into the water like a raptor and emerge with a crayfish clutched in his palm, its pincers snapping uselessly, trapped in a full nelson. When he sank a new one into the bucket, the captives clattered and fought for position on the growing pile, then settled.

Antonio figured that with the storms adding so much water to the river, the crayfish were trying to crawl ashore to avoid being washed away by the swifter current. He’d never eaten crayfish before but figured they were probably safe–the water wasn’t stagnant and people caught fish in that spot often enough.

Flores, who watched her brother from higher ground, was planning to steam them in coconut milk with chili. Antonio wanted his with beer and butter. Flores’s seven-year-old daughter Anjanet wasn’t going to try them at all. When Antonio caught one and missed the bucket she released a long shriek. As it raised its claws and snapped at Antonio, he crouched in a boxer’s stance and put up his dukes.

According to the Illinois Natural History Survey, 22 species of crayfish can be found in the state’s waters. Without seeing the crayfish in the Chicago River, the MWRD’s Irwin Polls and officials at Friends of the Chicago River guessed that they were a particularly nasty invasive species called Orconectes rusticus–or rusty crayfish–which first appeared in Illinois in the 70s after anglers used them as bait.

David Lodge, a biologist at the University of Notre Dame who takes a special interest in the rusty crayfish, looked at E-mailed pictures of Antonio’s haul and knew immediately that they weren’t Orconectes rusticus. “Holy mackerel!” he said. “These things are huge.” After I sent Lodge five specimens he confirmed his initial suspicion: they were Procambarus clarkii–Louisiana red swamp crayfish. That’s the tasty kind, served by the pound in New Orleans, or sometimes with remoulade.

At first he was astonished that the red swamp crayfish (or crawfish or crawdad) could be found this far north (it can regularly be found Downstate, in counties bordering the Mississippi River). It had to be some kind of record, he thought. But he did some reading and discovered that just this spring a biologist with the U.S. Fish and Wildlife Service published the results of a survey that found the red swamp crayfish living by a wastewater treatment plant in the Grand Calumet River near East Chicago, Indiana.

“The red swamp crayfish was collected downstream of the treatment plant’s outfall canal,” wrote Thomas Simon in the spring issue of Lakeline. “The introduction may be the result of either well-intentioned aquarists releasing their pets into the ‘wild’ or the unwanted pets may have been discarded down the toilet and were able to survive the treatment filtration process.” Introduced species like the rusty and red swamp crayfish displace native crayfish and prey on fish and aquatic plants. “The Louisiana swamp crayfish could be the next big mess in the Great Lakes,” says Simon, who first discovered the creature at Zion’s Illinois Beach State Park two years ago. “They’re really tolerant of contaminated sediments. They’re obviously tough animals because there’s nothing else that lives on the bottom of the Grand Calumet.”

The only person who didn’t seem surprised by the red swamp crayfish’s presence in the Chicago River, or by its early morning excursions into the grassy park, was Jay Huner, director of the University of Louisiana’s Crawfish Research Center and coauthor (with his wife) of Crawfish–Louisiana’s Crustacean Delight. “A Cajun down here would probably say, ‘What’s the big fuss about?'” says Huner. “We have roads that have to be shut down during heavy rainfall episodes, when sometimes thousands of the animals walk across the road. You hit them with the car, you slide everywhere.”

Huner says that even though P. clarkii is a species that likes to live in alternately wet and dry wetlands, it is “extremely plastic” and has been successfully introduced all over the world: from Japan to China to Switzerland to Spain to Ecuador to Hawaii. He figures there are probably Cajuns “all over Chicago” who get live crayfish shipped up for a taste of home. “Maybe some of them dump them in a ditch or something like that,” he says. “And secondarily, they’re very popular as pets. Someone gets tired of one and flushes it down the toilet and that’s how you get introductions.” It’s true that pet stores all over the city sell live crayfish, either as fish food or pets, though none of the fishmongers I talked to seemed to know exactly what species he had in stock.

P. clarkii burrow into riverbanks, says Huner, and sometimes they come out to forage at night, especially if it’s raining and the air keeps them moist. But when water levels rise, their burrows flood and they can’t get enough oxygen, so they head for higher ground. Biologists disagree over whether an introduction of huge quantities of sewage or pollutants would chase them out.

The Illinois Department of Public Health measures PCB levels in the tissues of fish found in the river and publishes meal advisories on its Web site. Sunfish are OK to eat once a week, largemouth bass once a month. But if you catch a carp longer than a foot–don’t eat it. The IDP doesn’t test crayfish. “These things are scavengers,” says Simon. “They’re omnivores. So they eat everything, and they’re just full of contaminants.”

“I probably wouldn’t suck the heads,” says Huner, referring to the Cajun talent for extracting the “fat,” or yellow liver, located in the animal’s head. “That’s where you’d find concentrations of heavy metals and other pollutants. But the tail muscle is typically, in quotes, clean.”

“Of course, they know how to cook them down there,” says Larry Page, a curator at the Florida Museum of Natural History, who wrote The Crayfishes and Shrimps of Illinois for the Illinois Natural History Survey. “I guess it seems like a normal thing to do, but I wouldn’t eat anything out of the Chicago River.”

Alody Flores didn’t think twice about it. On the Friday evening after the storm, two stockpots sat on her stove filled to the brim with bright red steamed crayfish and the kitchen was filled with a cloud of sweetness. One pot had been prepared her way, with coconut milk, the other Antonio’s–with beer. “Mmm, good!” she said, snapping a fat one in half and pulling out the tail meat. “You want to taste?” In the interest of science I did. It wasn’t bad, but her recipe notwithstanding, they’re better in Louisiana. Over the next two days Flores’s extended family polished off the rest of the Chicago River lobsters, and they’re all still alive to talk about it. Then again, no one sucked the heads.

Art accompanying story in printed newspaper (not available in this archive): photos/Jim Newberry.